document.write( "Question 1108990: A man is now five times as old as his daughter and five years ago the product of their ages was 105. Find their present ages. \n" ); document.write( "

Algebra.Com's Answer #724006 by ikleyn(52800) $\"\"$ $\"About$

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document.write( "M = 5*D               (1)\r\n" );
document.write( "(M-5)*(D-5) = 105     (2)\r\n" );
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document.write( "Substitute (1) into (2):\r\n" );
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document.write( "(5D-5)*(D-5) = 105\r\n" );
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document.write( "(D-1)*(D-5)  =  21\r\n" );
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document.write( "D^2 -D - 5D + 5 = 21\r\n" );
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document.write( "D^2 - 6D - 16 = 0\r\n" );
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document.write( "(D+2)*(D-8) = 0.\r\n" );
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document.write( "The positive root D= 8 is the only meaningful solution.\r\n" );
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document.write( "Answer.  Daughter is 8 years old.  Father is 40 years old.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Solved.\r
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\n" ); document.write( "There is a bunch of lessons on age word problems \r
\n" ); document.write( "\n" ); document.write( "    - Age problems and their solutions\r
\n" ); document.write( "\n" ); document.write( "    - A fresh formulation of a traditional age problem\r
\n" ); document.write( "\n" ); document.write( "    - Really intricate age word problem\r
\n" ); document.write( "\n" ); document.write( "    - Selected age word problems from the archive\r
\n" ); document.write( "\n" ); document.write( "    - Age problems for mental solution \r
\n" ); document.write( "\n" ); document.write( "in this site.\r
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\n" ); document.write( "\n" ); document.write( "Read them and become an expert in solving age problems.\r
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\n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic \"Age word problems\".\r
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\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
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